Method of forming slugs from rod stock

ABSTRACT

A method of forming slugs from rod stock which provides a workhardened center and completely eliminates burrs from the slugs. Suitably sized and straightened rod stock is fed to a first press where it is subjected to the action of a pair of cropping dies to form a cylindrical blank. The latter is fed into an extrusion cavity of a second press, the volume of which is slightly more than the volume of the cylindrical blank. When the cylindrical blank is impacted in this extrusion cavity a slug is formed with a work-hardened center and flat, unburred surfaces on the upper and lower peripheral surfaces thereof.

United States Patent Punch Press [2 J [72] Inventor Charles J. Beneke 2,223,107 11/1940 Hurschman 72/375 X Louisville, Ky. 2,804,621 9/1957 Winberg 72/337 X [211 Appl. No. 794,581 2.966,087 12/ l 960 Gray 83/247 [22] Fned 1969 Primary ExaminerCharles W. Lanham [4S] Patented July 27, 1971 Assistant Examiner-R. M. Rogers [731 Asslgnee Reynolds Metals Company Anome 01 P l L Gbb & Th

Richmond Va yenn, a mer yne, l s ompson [54] METHOD OF FORMING SLUGS FROM ROD STOCK 9 Claims, 8 Drawing Figs.

U.S. A method of fonning slugs from rod tuck 72/352' 29/1-22 provides a work-hardened center and completely eliminates [51] Int. Cl B21d 28/00, buns f the Slugs Suitably Sized and straightened rod stock 321d 22/00 Bzlk 21/06 is fed to a first press where it is subjected to the action ofa pair [50] Field of Search 72/339, f cropping dies to f a cylindrical blank The is f d 343; 85, 86; into an extrusion cavity ofa second press, the volume of which 29/ 1 12 is slightly more than the volume of the cylindrical blank. When the c lindrical blank is impacted in this extrusion cavity [56] nuances Cmgd a slug is foi 'med with a work-hardened center and flat, un- UNITED STATES PATENTS burred surfaces on the upper and lower peripheral surfaces 133,066 1 H1972 Stetson 29/].22 thereof.

Horizontal Press inishe g Product PATENTED JUL 2 7 I97! SHEET 2 BF 3 INVENTOR Ch ar/es J Bane/Q6 Z; M a ,4,

ATTORNEYS PATENTEU JUL2 1 I971 SHEET 3 OF 3 INVENTOR Charles J. Berle/re ATTORNEYS METHOD OF FORMING SLUGS FROM ROD STOCK This invention relates to the formation of slugs from rod stock and, more particularly, to the formation of such slugs which are completely free from burrs whereby subsequent machining operations including corner treatment and 'debur ring operations are eliminated.

Difficulty has been experienced in obtaining suitable slugs for use in making shells for projectiles and the like in that it is desirable to have the center of the slug work-hardened so that it will not be pierced when impacted by a firing pin. In addition the slug must be completely free from burrs and the like so that there will be no carryover defects from the slug when it is formed subsequently. These requirements have necessitated multiple operations in the past which have been both costly and time consuming.

In accordance with the present invention, the aforementioned problems are effectively overcome in an expeditious manner starting with inexpensive rod stock. The latter is fed into a first press and subjected to the action of a pair of cropping dies which produce a cylindrical burr-free blank in a single operation. The cylindrical blank is fed into an extrusion cavity of a second press the volume of which is slightly in excess of that of the cylindrical blank. When the cylindrical blank is impacted in the cavity of the second press, a final slug is produced directly therefrom which not only has a desired work-hardened center but is also burr-free. The latter feat is directly attributable to the previously described volumetric relationships whereby the slug has flat, unburred surfaces on its upper and lower peripheral surfaces. The unburred surfaces are obtained without machining or otherwise treating the slug. Control over the size of these flat surfaces may be used to compensate for small variations in the size of the cylindrical blank.

The rocess of this invention may be carried out on both aluminum, including alloys thereof, and steel. The process may be performed at room temperature and may proceed at rapid rates. The slug product with its work-hardened center and its burr-free edges is uniquely suited for subsequent forming operations in the manufacture of shells for projectiles and the like.

The inherent advantages and improvements of the present invention will become more readily apparent from a consideration of the following detailed description of the invention and by reference to the drawings in which:

FIG. I is a side elevation view, schematic in nature, illustrating the overall operation of the present invention;

FIG. 2 is a fragmentary side elevation view illustrating the output of a cropping die as viewed along line 2-2 of FIG. 1;

FIG. 3 is a cross-sectional view in elevation of an impacting operation which occurs as viewed along line 3-3 of FIG. 1;

FIG. 4 is a cross-sectional view similar to FIG. 3 illustrating a subsequent step in the impacting operation;

FIG. 5 is an enlarged crosssectional view of the blank formed in FIG. 4, drawn to an enlarged scale;

FIG. 6 is a side elevation view of a completed slug;

FIG. 7 is a top plan view of a completed slug of FIG. 6; and

FIG. 8 is a bottom view of the completed slug of FIG. 6.

Referring now to FIG. 1 of the drawings, there is illustrated rod stock, indicated generally at T0, fed into a punch press indicated generally at 112 at an angle A with respect to the horizontal. This rod stock has been previously sized and straightened in accordance with customary practice. Punch press 12 is shown to include a cropping die operation which employs an upper cropping die 14 and a lower cropping die M. The output of the cropping dies is carried by means of an inclined removal chute IS on which rod blanks slide by gravity into a hopper 21, the lower exit extremity of which is directly over an end of a conveyor 22. The latter transports the rod blanks 20 to an orienting mechanism 24 of a suitable type whereby the blanks are oriented for transfer by means of transfer feeder 26 to a horizontal press indicated generally 26. In the latter press, the rod blanks 20 are impacted to provide a finished product 30 which falls onto a removal conveyor 32 to be carried away for further processing.

Reference to FIG. 2 illustrates an upper dieholder structure 34 and a lower die holder structure 36 of punch press 12. A resilient support is provided between the upper die holder structure 34 and the lower die holder structure 36 by means of a pair of springs 38 which encircle a telescoping post structure 39 mounted on bascplate 40.

The operation of horizontal press 28 is depicted in FIGS. 3 and 4 wherein a ram 42 reciprocates so as to impact blank 20 between ram 42 and a female die ,member 44 which also serves as a knockout device. The female die member 44 is provided with a work-contacting surface 46 which is substantially disc-shaped in cross section. Horizontal press 28 is provided with a cavity 48 defined by the upper surface of female die member 44, the inner sides 49 of the press and the lower surface of ram 42. The cavity 48 has a volumetric capacity slightly in excess of the volume of the finished work product 30 for a purpose to be described hereinafter. The inner sides 49 of the press 28taper outwardly in the direction toward arm 42 to impact a slightly conical wall to the finished product 30 and to facilitate removal of product 30 from press 28. A push rod 50 is used to actuate the work knockout member after the ram 42 has compacted the rod blank 20.

Reference to FIG. 5 illustrates, in an enlarged scale, that after the ram 42 has compacted the rod blank 20 to effect an impact extrusion thereof and provide the finished product 30, leaving voids illustratedat 52, 54, 56 and 58 within cavity 48 which are not filled by the workpiece. This overcapacity of the cavity 48 of press 28 results in the production of beveled surfaces 60 and 62 on the finished product 30 which are burrfree.

FIGS. 6-8 illustrate the final configuration of the finish ed product 30 which in addition to the burr-free peripheral edges 60 and 62 is provided with a sloping surface 64 leading to a flat top surface 66. Finished product 30 further has a tapered sidewall 68 immediately above the beveled surface 62 and a flat bottom 70.

By virtue of the fact that the rod stock 10 is subjected to the action of cropping dies, there is no burr or fingerlike projection formed at the edges of rod bla'nks 20 which would be carried over and reappear as a flaw in the final product 30 after the impact extrusion operation. Therefore, a finished product 30 is provided which is burr-free. It has been found that the angle A in FIG. I should be approximately 12 for aluminum and aluminum alloys and should be approximately 7 for steel.

As a specific example of stock material, 6066-F aluminum alloy, as designated by the aluminum Association, measuring 1 inch in diameter was fed into press 12 at an angle A measuring 12. Cylindrical blanks varying in length from 1.735 inches to l .775 inches were cut from the bar stock, oriented and fed into prms 28. The blanks were impact extruded in press 28 to produce a finished product 30 measuring approximately 1.660 inches at bottom wall 70 measured to the tapered wall side 68 of bevel 62, a taper on wall 68 of 0.0025 inch and a distance across at the top of wall 68 of approximately 1.655 inches. Top wall 66 measured five-eighths inch in diameter and sloping surface 64 made an angle of 7 with respect to the horizontal. The height of the finished product 30 measured approximately 0.0670 inch between bottom wall 70 and top wall 66. The beveled surfaces 60 and 62 measured between one thirtysecond and one-sixteenth of an inch with this variation compensating for cylindrical blanks of varying lengths.

Other suitable rod stock materials include aluminum 1 -0, 1 l00F, 6070'F, 2024-0, 606l-Oand steel.

A significant feature of the present invention is a substantial reduction in waste as contrasted with previous attempts to form the blanks from sheet material where waste would customarily run from 35-40 percent.

While presently preferred embodiments of the present invention have been illustrated and described, it will be recognized that the invention may be otherwise variously embodied and practiced within the scope of the claims as follow:

What I claim is:

1. A method of forming a slug from rod stock, said method comprising the steps of a. feeding rod stock to a first press,

b. severing a portion of said rod stock to form a cylindrical blank.

c. feeding said cylindrical blank into an extrusion cavity in a second press, said extrusion cavity having a volume slightly in excess of the volume of said cylindrical blank,

d. and impacting said cylindrical blank to fill said cavity substantially thereby forming a slug having unburred surfaces on the upper and lower peripheral surfaces thereof.

2. A method of forming a slug from rod stock as defined in claim 1 wherein said step of severing a portion of said rod stock consists of subjecting said rod stock to a pair of cropping dies.

3. A method of forming a slug from rod stock as defined in claim 1 including the step of feeding said rod stock to said first press at an acute angle of about 12 to the horizontal wherein said rod stock is made from aluminum or aluminum alloy.

4. A method of forming a slug from rod stock as defined in claim 1 wherein said rod stock is made from steel and wherein said acute angle is about 7 to the horizontal.

5. A method of forming a slug from rod stock as defined in claim 1 including the additional step of orienting said cylindrical blank in a predetermined orientation prior to feeding said cylindrical blank into said extrusion cavity in said second press.

6. A method of forming a slug from rod stock as defined in claim 5 wherein said step of severing a portion of said rod stock consists of subjecting said rod stock to a pair of cropping dies.

7. A method of forming a slug from rod stock as defined in claim 5 including the step of feeding said rod stock to said first press at an acute angle of about 12 to the horizontal wherein said rod stock is made from aluminum or aluminum alloy.

8. A method of forming a slug from rod stock as defined in claim 5 wherein said rod stock is made from steel and said rod stock is inclined at an angle of about 7 to the horizontal.

9. A method of forming an article from a blank, said method comprising the steps of:

a. feeding said blank into a closable extrusion cavity of a press having dies of the closed die type, said extrusion cavity having a volume slightly in excess of the volume of said blank when said dies are closed,

b. and impacting said blank to conform it substantially to the configuration of said cavity and thereby forming an article having substantially unburred surfaces. 

1. A method of forming a slug from rod stock, said method comprising the steps of a. feeding rod stock to a first press, b. severing a portion of said rod stock to form a cylindrical blank. c. feeding said cylindrical blank into an extrusion cavity in a second press, said extrusion cavity having a volume slightly in excess of the volume of said cylindrical blank, d. and impacting said cylindrical blank to fill said cavity substantially thereby forming a slug having unburred surfaces on the upper and lower peripheral surfaces thereof.
 2. A method of forming a slug from rod stock as defined in claim 1 wherein said step of severing a portion of said rod stock consists of subjecting said rod stock to a pair of cropping dies.
 3. A method of forming a slug from rod stock as defined in claim 1 including the step of feeding said rod stock to said first press at an acute angle of about 12* to the horizontal wherein said rod stock is made from aluminum or aluminum alloy.
 4. A method of forming a slug from rod stock as defined in claim 1 wherein said rod stock is made from steel and wherein said acute angle is about 7* to the horizontal.
 5. A method of forming a slug from rod stock as defined in claim 1 including the additional step of orienting said cylindrical blank in a predetermined orientation prior to feeding said cylindrical blank into said extrusion cavity in said second press.
 6. A method of forming a slug from rod stock as defined in claim 5 wherein said step of severing a portion of said rod stock consists of subjecting said rod stock to a pair of cropping dies.
 7. A method of forming a slug from rod stock as defined in claim 5 including the step of feeding said rod stock to said first press at an acute angle of about 12* to the horizontal wherein said rod stock is made from aluminum or aluminum alloy.
 8. A method of forming a slug from rod stock as defined in claim 5 wherein said rod stock is made from steel and said rod stock is inclined at an angle of about 7* to the horizontal.
 9. A method of forming an article from a blank, said method comprising the steps of: a. feeding said blank into a closable extrusion cavity of a press having dies of the closed die type, said extrusion cavity having a volume slightly in excess of the volume of said blank when said dies are closed, b. and impacting said blank to conform it substantially to the configuration of said cavity and thereby forming an article having substantially unburred surfaces. 